XP UNC Connectivity Problem

[jmconsulting]

I checked the FAQ's but did not find solution.

I inhereted this problem, I would never have set it up this way but.....

Problem:
2 PC's in one workgroup (mshome)
PC1 XP Pro SP2
PC2 XP Pro SP1

3 PC's in another workgroup (lawoffice)
PC3 XP Pro SP1 (server)
PC4 XP Pro SP1
PC5 XP Home (notebook)

PC1 got hit hard with a hijack that would not allow IE, Network search or my computer to run (hard halt). Cleaned PC1 and got the apps back. I have access to Internet working. Attempt to connect to PC3 (server) and unavailable due to resource not restored. Ran everything that I could. PC2 has problems connecting to a UNC networked printer but can connect to server.

Other workgroup works fine. Is there anything known out there that can effect XP's ability to connect to resources via a UNC share?

Thanks....